It has been known to obtain a coated article having matted surface by electrocoating with electrodepositable paint containing internally crosslinked micro resin particles (hereinafter referred to as "micro gel particles") prepared by polymerizing an ethylenically unsaturated monomer (see Japanese Patent Publication (unexamined) Nos. 93762/1983 and 49766/1981). The micro gel particles are advantageous not only in providing matted surface, but also in coating properties and throwing power.
The micro gel particles, however, should be mixed with a resin which is water-soluble or water-dispersible and which has charges necessary for electrodeposition if it is applied for electrocoating, because they do not have suitable charges and are insoluble in an aqueous medium. On the other hand, the micro gel particles deteriorate storage stability and workability of electrocoating and it therefore is difficult to formulate in a large amount into a paint.
In order to improve the above defects, the present inventors propose in U.S. Pat. No. 4,788,246 that cationic micro gel particles are prepared by crosslinking a cationic resin and a crosslinking agent. In this patent, there is no description with respect to particles prepared by a radical addition reaction.